Cognito sign in verification email not getting username

I have set up cognito but the email verification page is not getting my username properly (printing placeholders).

My cognito settings as follows

and the verification email that I received is as follows:

Do I have to use custom lambda triggers for this? (How do I achieve that)

Update: Use "event.userName" to get the username in the lambda trigger

if(event.triggerSource === "CustomMessage_ForgotPassword") {
            // Ensure that your message contains event.request.codeParameter. This is the placeholder for code that will be sent
            event.response.smsMessage = "You requested to reset your password " + event.request.codeParameter;
            event.response.emailSubject = "You requested to reset your password: " + event.userName;
            event.response.emailMessage = 'Hi, Username:' + event.userName+' , '+ event.request.codeParameter + ' is your verification code '  ;
}